This application claims priority of Taiwan Patent Application No. 90217629, filed on Oct. 16, 2001.
1. Field of the Invention
The invention relates to a signal-transmitting apparatus, more particularly to a signal-transmitting apparatus for a cable television system that is provided with an electromagnetic radiation shielding assembly which is space-saving.
2. Description of the Related Art
A conventional signal-transmitting apparatus, such as an amplifier, a distributor, or a diverter, for use in a cable television system requires a power source-connecting tube for receiving a power source terminal so as to connect to an electric power supply for supplying operating power to electronic components in the apparatus. However, when electric currents flow through the apparatus, if no shielding means is provided, the electromagnetic radiation thus generated will interfere with the operation of the electronic components within the apparatus or the input/output ports, thereby adversely affecting the quality of signal transmission.
FIGS. 1 and 2 show a conventional signal-transmitting apparatus with an electromagnetic radiation shielding member which is adapted for use in a conventional cable television system. The apparatus, which is exemplified herein using an amplifier, includes a casing 90 having a metal first partition 91 disposed near a corner of the casing 90 and confining a corner space, a metal top cover 92 disposed on top of the first partition 91 to close the corner space, a metal second partition 93 disposed within the corner space and having a top edge formed with an indentation 931, and a capacitor 94 disposed in the indentation 931. The capacitor 94 includes a main body 942, and opposite outer and inner contact pins 941, 943. The outer contact pin 941 is soldered to an inner end of a power source terminal 96 extending through a power source-connecting tube 95. The main body 942 is mounted in the indentation 931, and is connected electrically to the top cover 92 so as to constitute a grounding circuit when the top cover 92 is put in place. The inner contact pin 943 is connected electrically to a contact on a circuit board 98 disposed within the corner space via a lead wire 97.
Although the first and second partitions 91, 93 and the top cover 92 together can serve to shield the electromagnetic radiation generated by the terminal 96 during operation, the first and second partitions 91, 93 occupy a relatively large amount of the space available in the casing 90. Hence, the overall size of the apparatus cannot be reduced. Besides, if the top cover 92 is not in sealing contact with the top edge of the second partition 93, the electromagnetic radiation from the terminal 96 may still escape through a clearance between the top cover 92 and the second partition 93.
Therefore, the main object of the present invention is to provide a signal-transmitting apparatus with an electromagnetic radiation shielding assembly that utilizes a power source-connecting tube of the apparatus to serve as an electromagnetic radiation shielding member to thereby enable a reduction in the size of the apparatus.
Accordingly, a signal-transmitting apparatus for a cable television system of the present invention is adapted to permit insertion of a power source terminal therein and includes:
a body including a metal casing and a circuit board that is fixed in the casing, the casing having a side wall with a capacitor-mounting hole, and a power source-connecting tube which is formed integrally with the side wall at an end thereof and which defines a central hole that is in communication with the capacitor-mounting hole in the side wall;
a conductive terminal clip disposed within the central hole in the power source-connecting tube, the clip having a clamping end that is adapted to clamp the terminal, and a conducting end; and
a capacitor unit disposed in the central hole in the power source-connecting tube and received fittingly within the capacitor-mounting hole in the side wall, the capacitor unit including a capacitor, which has
a main body in electrical connection with the casing,
an outer contact pin in electrical connection with the conducting end of the clip, and
an inner contact pin in electrical connection with the circuit board.